Prometheus 2.0 migration guide

    The format of the Prometheus command line flags has changed. Instead of asingle dash, all flags now use a double dash. Common flags (,—web.listen-address and —web.external-url) are still the same but beyondthat, almost all the storage-related flags have been removed.

    Some notable flags which have been removed:

    • -alertmanager.url In Prometheus 2.0, the command line flags for configuringa static Alertmanager URL have been removed. Alertmanager must now bediscovered via service discovery, see Alertmanager service discovery.

    • -log.format In Prometheus 2.0 logs can only be streamed to standard error.

    • -query.staleness-delta has been renamed to —query.lookback-delta; Prometheus2.0 introduces a new mechanism for handling staleness, see .

    • -storage.local.* Prometheus 2.0 introduces a new storage engine, as such allflags relating to the old engine have been removed. For information on thenew engine, see Storage.

    • -storage.remote.* Prometheus 2.0 has removed the already deprecated remotestorage flags, and will fail to start if they are supplied. To write toInfluxDB, Graphite, or OpenTSDB use the relevant storage adapter.

    Alertmanager service discovery

    Would be replaced with the following in the prometheus.yml config file:

    1. alerting:
    2.   alertmanagers:
    3.   - static_configs:
    4.     - targets:

    You can also use all the usual Prometheus service discovery integrations andrelabeling in your Alertmanager configuration. This snippet instructsPrometheus to search for Kubernetes pods, in the default namespace, with thelabel name: alertmanager and with a non-empty port.

    1. alerting:
    2.   alertmanagers:
    3.   - kubernetes_sd_configs:
    4.       - role: pod
    6.       ca_file: /var/run/secrets/kubernetes.io/serviceaccount/ca.crt
    7.     bearer_token_file: /var/run/secrets/kubernetes.io/serviceaccount/token
    8.     relabel_configs:
    9.     - source_labels: [__meta_kubernetes_pod_label_name]
    10.       regex: alertmanager
    11.       action: keep
    12.     - source_labels: [__meta_kubernetes_namespace]
    13.       regex: default
    14.       action: keep
    15.     - source_labels: [__meta_kubernetes_pod_container_port_number]
    16.       regex:
    17.       action: drop

    The format for configuring alerting and recording rules has been changed to YAML.An example of a recording rule and alert in the old format:

    Would look like this:

    1. - name: example.rules
    2.   rules:
    3.   - record: job:request_duration_seconds:histogram_quantile99
    4.     expr: histogram_quantile(0.99, sum(rate(request_duration_seconds_bucket[1m]))
    5.       BY (le, job))
    6.   - alert: FrontendRequestLatency
    7.     expr: job:request_duration_seconds:histogram_quantile99{job="frontend"} > 0.1
    9.     annotations:
    10.       summary: High frontend request latency

    To help with the change, the promtool tool has a mode to automate the rules conversion. Given a .rules file, it will output a .rules.yml file in thenew format. For example:

    1. $ promtool update rules example.rules

    Note that you will need to use promtool from 2.0, not 1.8.

    Storage

    The data format in Prometheus 2.0 has completely changed and is not backwardscompatible with 1.8. To retain access to your historic monitoring data werecommend you run a non-scraping Prometheus instance running at least version1.8.1 in parallel with your Prometheus 2.0 instance, and have the new serverread existing data from the old one via the remote read protocol.

    Prometheus 2.0 can then be started (on the same machine) with the following flags:

    1. $ ./prometheus-2.0.0.linux-amd64/prometheus --config.file prometheus.yml

    Where prometheus.yml contains in addition to your full existing configuration, the stanza:

    1. remote_read:
    2.   - url: "http://localhost:9094/api/v1/read"

    The following features have been removed from PromQL:

    • drop_common_labels function - the without aggregation modifier should be usedinstead.
    • keep_common aggregation modifier - the by modifier should be used instead.
    • count_scalar function - use cases are better handled by absent() or correctpropagation of labels in operations.See for moredetails.

    Miscellaneous

    The Prometheus Docker image is now built to . If youwant the Prometheus UI/API to listen on a low port number (say, port 80), you'llneed to override it. For Kubernetes, you would use the following YAML:

    See Configure a Security Context for a Pod or Containerfor more details.

    If you're using Docker, then the following snippet would be used:

      Prometheus lifecycle

      If you use the Prometheus /-/reload HTTP endpoint to automatically reload yourPrometheus config when it changes,these endpoints are disabled by default for security reasons in Prometheus 2.0.To enable them, set the —web.enable-lifecycle flag.